Centrifugal compressor



June 24, l947- G. F. wlsLlcENus v CENTRIFUGAL COMPRESSOR Filed llarch 2, 1944 4 sheets-sheet 1 Enrqe 1E Wislmenua I lsNToR ATTORN June 24,y 1947. G, F, W|SL|CENU$ 2,422,763

CENTRIFUGAL COMPRESSOR Filed larch 2, 1944 Y 4 Sheets-Sheet 2 Fl y. v IN ENTOR i v BY i f TTORNE` June 24 1947- G. F. wlsLlcENus u CENTRIFUGAL COMPRESSOR Filed Ilarh 2, 1944 4 Sheets-Sheet 3 Eenr'qe IE' Wislicenus I VENTOR MTQRNEY June 24 1941 G. F. wlsLlcENus y CENTRIFUGL CUMPRESSOR Filed llarch 2, 1944 4 Sheets-Sheet 4 Ele mqe T.' Wislicenua HVVENTOR ATTORNEY Patented June 24, 1947 I lc,lirx'rlurudai. COMPRESSOR George F. Wislicenus, Summit, N. J., assigner to Worthington Pump andMachinery Corporation, Harrison, N; J., a corporation of Delaware Application March 2, 1944, Serial No. 524,712

29 Claims.

, -1 This invention relates to centrifugal machines, and more particularly to a centrifugal compressor embodying a novel casing. and rotor structure.

An object of the present invention is to provide a centrifugal compressor of the multistage type in which the casing and rotor thereof are of such design as to permit axial removal of the rotor intact from the casing by merely detaching one or both end covers of the casing.

Another object is to provide a centrifugal ma- -chine wherein the rotor embodies individual stage impellers having inward and outward flow fluid delecting or guiding varies of such construction and arrangement as to unite the impellers into a unitary structure in such manner as to eliminate the necessity of a rotor shaft.

Another object is to provide a centrifugal machine wherein stage impellers are xedly related in such manner as to eliminate the necessity of a rotor shaft as far as the inner portions of the machine are concerned, and in which coaxial means areinterposed between the impellers for hydraulic reasons only to eliminate instability of the flow at the center of rotation.

Another object is to provide a centrifugal macompressor of the multistage type wherein the impellers of the rotor are permanently connected into a unitary structure, in which the impellers embody uid passages generally U-shaped in cross section and open through the annular perimeter o'f the rotor, and in which the annular perimeter of the rotor and the casing are provided with co-acting wearing surfaces of such relative diameters as to permit axial removal of. the rotor intact from the casing without necessitating horizontal or vertical separation of the casing.

With these and other objects in view, as may appear from the accompanying specification, the invention consists of various features of construction and combination of parts, which will be rst described in connection with the accompanying drawings, showing a centrifugal compressor of a preferred form embodying the invention, and'the features forming the invention will be specifically pointed out in the claims.

In the drawings: Figure y1 is a longitudinal sectional view of a centrifugal compressor in accordance with the g5 present invention.

chine having a rotor provided with fluid deflectt ing or guiding vanes co-acting with the body structure of the rotor in such manner as to function as strut means for resisting deflection of the rotor.

Another object is to provide a centrifugal compressor of the multistage type which is characterized by exceptionally high compressing eniciency in that the inlet (eye)y diameter of the outward flow impellers maybe made the same as for a corresponding single stage overhung pump, the latter being the type of pump with which the highest pump efficiencies have been obtained in the past.

Another object is to provide a centrifugal compressor embodying a casing structure comprising an assembly -of casing rings or stage pieces in which the stage distances may be assured through accurate pre-machining of the individual pieces, and in which the design will be essentially the same for positive, zero .or negative pre-rotation' at the inlet of each inward ow impeller section.

Another object is to provide a centrifugal compressor of the multi-stage type wherein the rotor comprises impellers permanently or semi-permanently connected into a unitary structure', and in which the running joints in the casing and the Figure 2 is an enlarged 'sectional view taken along the line 2-2 of Figure 1.

Figure 3 is an enlarged, fragmentary view of the impeller structure.

sectional Figure 4 is an enlarged sectional view taken along the line 4-4 of Figure 1.

Figure 5 is a fragmentary,l longitudinal sectional view of a modified form of casing struc` ture.

Figure 6 is an enlarged, fragmentary sectional view of the casing structure illustrating a system of inlet guide vanes for positive pre-rotation of the uid.

Figure I is an enlarged, fragmentary sectional view illustrating a system of inlet guide vanes for zero pre-rotation of the fluid.

Referring more `particularly to the drawings, Figure `1 illustrates a compressor casing III within which is contained a rotor II havingaxially spaced but co-axial shaft parts I2 and I3. Bearings I4 and I5 at the opposite ends of the casing I0 support the shaft parts I2 and I3, respectively. The rst stage end of the rotor Il is bolted at I6 to the shaft part I2, while the other end of the rotor is bolted at I1 to the shaft part I3. The' driving shaft part I3 maybe connected in any suitable manner to any approved type of almenos specific type of service for which the compressor is designed.

The rotor II has an annular contour of uniform diameter from end to end and includes annular and axially spaced fluid passages I3 generally U-shaped in cross-section. The legs I9 and 29 of the respective passages I8 open outwardlythrough the annular perimeter of the rotor and comprise fluid inlets and fluid outlets, respectively. Inward flow vanes 2| are contained in the inlets I9 and Aoutward flow vanes 22 are contained in the outlets 20. Accordingly, the'rotor Il embodies a. series of stage impellers 23. All the impellers are of similar construction except as to width and volumetric capacity with the exception of the rst stage impeller, the latter having a uid outlet passage`24 communicating with aneye 25 having communication with a suction inlet 26 through which the gas or vapor can enter the compressor. Outward flow vanes 21 are provided in the passage 24.

The casing I8 is provided with double or twin volutes 28 in the respective stages of the compressor as clearly shown in Figure 4 of .the drawings, and each comprising two volute passages 29 and 38 for co-action with the fluid passages I8 and 25. The defining walls 3I and 32 curve circumferentially and laterally so that the volute passages 29 and 30 have outlets 33 and inlets 34 communicating with the inlet and outlet legs I9 and 28, respectively. Thus the fluid passages I8 are in series communication with the stage volute passages 29 and 30, and the outlet 28 in the last stage of the compressor communicates with volute passages in the casing I0 and leading into a discharge 36.

In the present construction of centrifugal machine or compressor for compressing gas or vapor, the pressure of uid compressed increases in geometric progression from stage to stage with the absolute discharge pressure of each stage bearing approximately a constant ratio to its inlet pressure. By reference to Figure 1, it will be noted that, notwithstanding the uniform diameter of all the impellers and the casing chamber within which the rotor is contained, the fluid passages in the rotor I I and the casing I0 are of decreasing volumetric capacities successively from the first through the last stage of the compressor.

Specifically, the rotor II comprises two end discs 31 and 38 to which the stub shafts I2 and I3 are respectively connected as shown in Figure 1, and inlet side discs or webs 39 and outlet side discs or webs 40 which are arranged in co-axial relationship with and between the two end discs 31 and 38. One disc 39 lies face to face with the enddisc 31 and is fixed thereto, while each of the remaining inlet-side discs 39 lies face to face with outlet-side disc -40 and is fixed thereto so that the rotor includes a series of annular wall structures 4I arranged at right angles to the axis of the rotor and isolating the fluid passages I8 and 24 one from the other.

Annular flanges 42 are provided on the inner faces of the discs 39 which flanges have peripheral engagement with annular shoulders 43 on the discs 40 and the end disc 31, as clearly shown in Figure 3 of the drawings. The flanges 42 and the shoulders 43 are of smaller diameters than the discs'39 and 40 and the end disc 31, with the marginal facesA of the discs 39 angled away from their respective discs 48 andthe end disc 31 to provide circumferential channels 44 for the reception of welds 45 which connect the paired vdiscs into the unit wall structures 4I.

Connectors 46 are interposed between the wall structures 4I in co-axial relationship at the axis 5 of the rotor I I. One end of each connector 46 is mounted on a short post or axial extension." on its respective disc 39., and the opposite ends of the connectorsare pressed into shallow bores 48 in the respective discs 40 and the end disc 38. Small ports 49 are provided in the discs 39 which permit air to escape from between the united discs during construction of the welds 45. The connectors 46 may be in the form of cylindrical tubes as shown in Figure l of the drawings, if desired.

If it is so desired, the discs 39 and 40 may be of dished contour, with the discs 39 dished in a greater degree, so that the wall structures 4I are of hollow formation. While a, dished contour is absent in the end disc 31, the associated disc 39 is dished in such a degree that the wall structure 4I at the first stage of the compressor is also of hollow formation. However, this construction is not essential to the design or advantages of the invention.

Shroud ring assemblies 58 are arranged between the Wall structures 4I and are spaced from the concaved faces 5| on the discs 39 and 40 and the end disc 38 and co-act therewith and with the tubes 46 to define the respective fluid passages I8'. While the tubes 46 are located at the axis of the rotor, these tubes perform no shaft function as far as the transmission of power is concerned, but are included in the rotor structure between the impellers for hydraulic reasons only to eliininate instability of flow at the center of rotation.

Means for xedly connecting all the wall structures 4| into the rotor structure II comprise the' shroud ring assemblies 50 and the inward now vanes 2l and the outward flow vanes 22,

and is provided with a wearing surface coacting with the wearing surface 56 on a casing ring 51 attached to the casing I0.

Specifically, the shroud ring assemblies defining one wall of the respective fluid passages I8 comprise ring sections 58 to which the inward flow vanes 2| are i'ixedly connected, these varies being xedly connected with the respective discs 60 39. Second ring sections 59 are iixedly connected with the respective outward flow vanes 22, the

latter being xedly connected with the respective discs 40 and the end disc 38.4 Annular shoulders 60 and 6I are formed on the respective ring sections 58 and 59 which engage one with the other to accurately align the paired ring sections in true concentric relationship. The paired ring sections 58 and 59 have end face engagement at 62 and are fixedly connected together by bolts 63. Rings 64 engage at 55 with the respective ring' sections 58 and. include annular Walls 66 which are threadedly connected at 61 with the ring sections 59. 'I'he walls 66 have edge engagement with stop flanges 68 on their respective ring sections 59. All the walls 66 have wearing sur.

-structures 4|.

faces 459 arranged in co-active relationship with wearing surfaces 19 on casing rings 1| attached to the casing Ill. v

While the shroud ring assemblies 59 are of hollow formation and the bolts 83 are accessible only from a position inside the assemblies, the bolts 83 are made easily accessible by unthreading the peripheral rings 64 from their respective ring sections 59 and then shifting the peripheral rings 54 axially to one side sufficiently far to expose the bolts. These bolts are preferably of the type having sockets in their heads to facilitate manipulation thereof with a suitable tool.

' Peripheral rings 12 are included in the wall These rings embrace the annular perimeters of their respective discs 39 and 40 and the end disc 31, and the rings are threadedly connected at 13 with the discs 40 and the end disc 31. Stop flanges 14 are provided'on the'discs 49 and the end disc 31 for engagement with their respective peripheral rings 12. Wearing surfaces 15 are provided on the peripheral rings 12, `these wearing surfaces being arranged in co-active relationship with wearing surfaces 16 on casing rings 11 attached to the casing III.

In Figure 1, the casing I comprises stage pieces or annular casing members 18 and 15| arranged alternately and in end to end engagement and two end pieces or members 8|!k and 8|. All the members 18, 19, 80, and 8| are flanged at 82 and connected into a unitary structure by blots 83. The members 18, 19, and the end member 80 join in the planes of the respective wall structures 4| and shroud ring assemblies 50, with the exception of rst and last stage shroud ring assemblies in the compressor. The suction inlet 26l is contained inthe end member 80, while the latter member and the `members 18 and 19 are internally contoured to provide the volute passages 29, 30, and35. The last stage member 18 differs from the remainingmem-bers 18 in that the volute passages 35' are contained entirely within this member, whereas the volute passages 29 and 30 are defined or completed only through uniting of the remaining members 18 and 19 and the end member 80. End covers 84 and 85 are bolted to the end members, 80 and 8|, respectively. The bearing I4 is carried by the end cover 84 and the bearing I5 is carried by the end cover 85. f

The wearing surfaces 55, 69, andy 15 on the rotor arel of the same diameter. This is also true of the wearing surfaces 58, 10, and 16 in the casing I0, these wearing surfaces constituting the smallest inside diameter of the casing I0. Accordingly, the rotor may be axially removed intact from the casing III without removing or opening any stationary parts except one or both end covers 84 and 85. Since the wearing Vsurfaces on the rotor are of diameters at least equal to the outside diameters of the respective impellers, the centrifugal machine herein described is completely devoid of any stationary parts which reach between the impellers of the individual stages.

The casing III, which contains al1 the' stationary iiuid passages, need not be parted eitherhori zontally in the plane of itsl axis or vertically at right angles to its axis. In addition, the running joints in thel casing as well as on the rotor can be machined in one setting to automatically assure perfect alignment. The rotor'may also be dynamically balanced as a whole. Provision of inward flow vanes in the rotating inlet fluid passage make the multistage rotor very 'bending- Ans ture of Figure '6 is identical with that of Figurestil! without depending in any way 4on shaft stifness, since the inward flow and outward iiowv and 22 have their greater portions lying at the same radial distances from the axis of the rotor, and thering sections 58 and 58 abut face to face at l62 at the same radial distances from the axis of the rotor. All the foregoing radial distances including the circumferential welds 44, terminate closely adjacent the maximum diameter of the rotor. Thus the inward flow and outward now vanes function additionally as strut means coacting with the wall structures 4| and the shroud ring assemblies 50 to resist deflection of the rotor. f

The 'presence of inward ow vanes or impellers make it possible to design highly eilicient outward flow impellers with considerably steeper vanes than used so far in highly efficient single stage centrifugal machines. Increased steepness of the vanes make the outward flow impellers more va resistant against high centrifugal forces, encountered in high head compressors. The inward flow varies 2| with their very flat outer ends dene smaller maximum diameters than the out? ward ilow vanes 22 in order to keep the centrifugal forces low.

The present centrifugal machine. structure is' such that 'the design..y -will be essentially the same for positive, zero or negative prerotation at the inlet of veach inward ow impeller section. Figures 1 and 2 illustrate the casing I0 as being provided with inlet guide varies 88 for negative prerotation at the inlet of each inward iiow impeller section. The vanes in each set are fixedly connected with two annular members 81, and these annular members are` connected with some of the walls 88 comprising portions of the respective casing members 18, 18, and 80 defining the respective fluid` outlets 33 and iluid inlets 34, as shown in Figure 1. The casing rings 51, 1|, .and 11 are also attached to the walls 88 and are held in place by split locking rings 89.

Another advantage of the centrifugal machine structure shown resides, in the fact that the inlet (eye) diameter of the outward flow impellers can Abe vmade the same as for-a corresponding single stage overhung pump, the latter being the type of pump with which the highest pump-eiiciencies have been obtained in the past. Heretofore, considerable diiiiculty has been experiencedzineectively securing impellers to their supporting shaft, particularly in high speed machines. The kcentrifugal stresses in a bored member rotated at high speed are at their maximum at the center hole. Even though the members are fitted tightly to the shaft, the centrifugal stresses are such as to tend to loosen the members so that it is diflicult to maintain a tight fit. In the construction shown, the impellers are effectively connected into a unitary structure through the medium of the vane structure and do not depend upon a shaft mount such as has been employed in the past.

In Figure 6, the centrifugal machine structure shown therein is equipped with inlet guide vanes 90 for positive prerotation at the inlet of the inward flow impeller. In other respects the struc- 2. The same holds true of Figure 7 wherein inlet guide vanes 9| for zero prerotation at inlet of the inward flow impeller section are shown. Obvious-v ly, adjustable guide vanes may be employed at Since the multistage rotor'll is axially removable intact from the casing I0, the casing may be cast in one piece. The advantages of building up the casing of individual and small castings resides in the simplification of foundry problems and low pattern'costs, This type of construction also facilitates cleaning of the fluid passages, and the exact stage distances are assured by premachining the individual casing pieces before assembling the pieces into a finished casing structure. Final machining of the casing is done after the casing pieces have connected together.

In Figure l, the casing members 18 and 'I9 are contoured to provide cooling chambers 92 between the stages ofthe'machine. Larger cooling chambers 93 are provided in the structure of Figure 5, wherein the casing is built up of casing members 94 and 95 and two end members` and 91 of the same general structure as the parts 18, 19, 80, and 9|, respectively, of Figure l. However, thel parts 94, 95, and 96 are connectedinto a. unitary structure by shellksections 98 arranged end to end about the members 94 and 95 and secured intoa connected structure by welds 98','which welds also, xedly relate the members 94 and 95. The members 94 and 95 and the shell sections 98 define the cooling chambers 93.

Figure 1 illustrates the end member 8| as being provided with a wearing sleeve 99 which isl mounted inside the end member and encircles a sleeve bolted at lill to the end member 38.

A balancing drum |02 is attached to the end member 38. y

In assembling the rotor the discs in the respective wall structures 4| are first united by the welds 45. One peripheral ring 64 is inserted over each set of inward flow vanes 2 I. The wall structures. 4| and the tubes 46 are then assembled and connected together stage by stage. As each wall structure 4| is placed in position, axial alignment is assured through engagement of the shoulders 60 and 6| one with the other on the ring sections 58 and 59, respectively. Tightening Vof the bolts 63 brings the ring sections 58 and 59 into face engagement at 62, which automatically determines the axial spacing of the wall structures. The peripheral rings 64 are threaded home after tightening the bolts 63 in their respective shroud ring assembly 50. It will thus be seen that the individual parts o'f the rotor may be easily assembled and connected into a unitary structure which slips easily into position in the What is claimed is:

1. In a centrifugal machine, a casing having a rotor chamber and a suction inlet and a discharge respectively communicating with said chamber, said casing having axially spaced stage fluid passages respectively communicating with said chamber, a rotor in said chamber, said rotor comprising stage impellers fixedly related in end to end relationship and each having a fluid passage generally U-shaped in cross-section, said second mentioned fluid passages arranged in operative series communication with said rstmentioned fluid passages and with said suction inlet and said discharge to provide a continuous fiuid passage from said suction inlet to said discharge, inward flow and outward flow uid defiecting vanes in the respective second mentioned fluidpassages, said vanes being located at such radial distances from the axis of the rotor and co-acting with their respective impellers so as to resist deflection of the lrotor without aid of an axial shaft, said impellers comprising axially spaced annular wall structures, annular spacers between said wall structures, shroud rings located between said wall structure, said wall structures, said spacers and said shroud rings being contoured to define said second mentioned fluid passages, said'shroud rings comprising sections and the sections in each impeller being respectively connected with the inward and outward flow vanes therein, said casing having wearing surfaces in the planes of said wall structures arranged in co-active relationship with said first mentioned wearing surfaces, saidisecond mentioned wearing surfaces having diameters at least equal to the outside diameters of the impellers whereby the rotor may be removed intact from said chamber.

2. In a centrifugal machine for compressing gas or vapor, a casing having stage uid passages, a rotor in said chamber, said rotor comprising stage impellers arranged end to end, said fluid passages and said impellers decreasing in volumetric capacities from the first stage through the final discharge stage, said impellers including wall structures and shroud rings lco-acting therewith to provide uid passages generally U-shaped in cross-section, inward flow and out-- ward now vanes in the respective second-mentioned iiuid passages, said inward ow and outward flow vanes being xediy related to their respective shroud rings and wall structures, means for connecting said impellers into a unitary structure, said connecting means, said shroud rings and said inward flow and outward ow vanes being located at such radial distances from the axis of the rotor as to make the rotor deection resistant without the aid of an axial shaft, and stub shafts at the ends of the rotor for rotatably supporting the latter in said casing.

3. In la centrifugal machine for compressing gas or vapor, a casing having stage fluid passages, a rotor in said chamber, said rotor comprising stage impellers arranged end to end, said fluid passages and said impellers decreasing in volumetric capacities from the first stage through the final discharge stage, said impellers comprising wall structures and cylindrical spacers between the wall structure at the axis of the` rotor, shroud rings positioned between said wall structures and co-acting with the latter and said spacers to provide fluid passages generally U-shaped in cross-section, inward flow and outward flow vanes in the respective second mentioned nuid passages, said inward flow and out- Y 9 v. ward ow vanes being iixedly attached to thei respective shroud rings and wall structures, said cylindrical spacers connecting said impellers into a unitary structure, said spacers, said shroud rings Aand said inward flow and outward iiow vanes being located at such radial distances from the axis of the rotor as to make the rotor deilection resistant without the aid of an axial shaft and co-axial shaft elements at the ends of the -rotor for rotatably supporting the rotor in said casing.

4. In a centrifugal machine for compressing gas-or vapor, a casing having stage fluid passages,

a rotor in said chamber, said rotor comprising stage impellers arranged end to end, said uid passages and said impellers decreasing in volumetric capacitiesfrom the iirstl stage through the final discharge stage, said impellers including wall structures and shroud rings co-acting therewith to provide fluid passages generally U-shaped in cross-section, inward now and outward ow vanes in the respective second-mentioned uid passages, said inward flow and outward flow vanes being fixed to their respective shroud rings and wall structures, means for connecting said impellers into a unitary structure, said means, said shroud rings and said inward flow and outward flow vanes being located at such radial distances from the axis of the rotor as to make the rotor deflection resistant without the aid of an axial shaft, stub shafts at the' ends of the rotor for rotatably supporting the latter in said'casing. said casing having ywearing surfaces, said wall structures and said shroud rings having wearing surfaces co-acting with the respective first-mentioned wearing surfaces, and said second mentioned wearing surfaces having diameters at least end, said iiuid passages and said impellers deequal to the outside diameters of the respective I impellers.

5; In a lcentrifugal machine for compressing gas or vapor, a casing having stage fluid passages, a rotor in said chamber, said rotor comprising stage impellers arranged end to end, said fluid passages and said impellers decreasing in volumetric capacities from the first stage through the final discharge stage, said impellers comprising wall structures and cylindrical spacers between the wall structure at the axis of the rotor, shroud rings positioned between said wall structures and co-acting with the latter and said spacers to provide fluid passages generally U-shaped in crosssection, inward flow and outward flow vanes in the respective second mentioned uid passages, said inward flow and outward flow vanes being fixed to their.respective shroud rings and wall structures, means for connecting said impellers in a unitary structure, said means, said shroud rings and said inward flow and outward iiow vanes being located at such radial distances from the axis of the rotor as to make the rotor deiiection resistant without the aid of an axial shaft, stub shafts at the ends of the rotor for rotatably supporting the rotor in said casing, said casing sure of each stage bearing a substantially constant ratio to its inlet pressure, a casing having stage iiuid passages, a rotor in said chamber, said creasing in volumetric capacities from the first stage through the final discharge stage, said impellers comprising wall structures and cylindrical spacers between the wall structure at the axis of the rotor, shroud rings positioned between said wall structures and co-acting with the latter and said spacers to provide fluid passages generally U-shaped in cross-section, inward ow and outward flow vanes in the respective second mentioned uid passages, said inward ow and out-- ward ow vanes being fixed to their respective shroud rings and wall structures, means for connecting said impellers in a unitary structure, said means, said shroud rings and said inward ow and outward ilo'w vanes being located at such radial distances from the axis ofthe rotor as to make the rotor deflection resistant without the aid of an axial shaft, co-axial shaft elements at the ends of the rotor for rotatably supporting the rotor in said casing, said casing comprising annular members arranged end to end and secured into' a unitary structure, inlet guide vanes for zero prerotation oi' the iluid at the inlets of the respective second mentioned iluid passages, and said inlet guide vanes being secured between certain of said annular members.

'1. In a centrifugal machine, a casing having stage fluid passages, a rotor in said chamber, said rotor comprising stage impellers arranged end to end, said impellers lcomprising wall structures and cylindrical spacers between the wall structure at the axis of the rotor, shroud rings positioned between said wall structures and co-acting with the latter vand said spacers to provide uid passages generally U-shaped incross-section, inward flow and outward flow vanes in the respective second mentioned iiuid passages, said inward ow and outward iiow vanes being xed to their respective. shroud rings and wall structures, means for connecting said iinpellers in a unitary structure, said means, said shroud rings and said inward flow and outward ow vanes being located at such radial distances from the axis of the rotor as to make the rotor deflection resistant without the aid of an axial shaft, stubshafts at -the ends of the rotor for rotatably supporting the rotor in said casing, said casing comprising annular members arranged end to end and secured into a unitary structure, and inlet guide vanes for negative prerotation at the inlets of the respective second mentioned uid passages, said inlet guide vanes being secured between certain of said annular members.

8. In a centrifugal machine for compressing and outward iiow vanes in the respective second mentioned fluid passages, said inward ow and' outward flow vanes being fixed to their respective shroud rings and wall structures, said cylindrical spacersv connecting said impellers in a unitary structure, said cylindrical spacers, said shroud rings and said inward ow and outward flow vanes being located at such radial distances from the axis of the rotor as to make the rotor deflection resistant without the aid of an axial rotatably supporting the rotor in said casing. and;

said casing comprising annular members arranged end to end and bolted into a unitary structure, said first mentioned iluid passages comprising twin volutes at each stage of the machine. said annular members being internallycontoured to4 denne said twin volutes when assembled end to end.

' 9. In a centrifugal machine, a casing having stage iluid passages, a rotor in said chambers. said rotor comprising stage impellers arranged end to end, said impellers comprising wall strucnn'es and cylindrical spacers between thewall structure at the axis of the rotor, shroud rings positioned between said wall structures and coacting with the latter and said spacers to provide iluid passages generally U-shaped in crosssection, inward ilowand outward flow vanes in the respective second mentioned iiuid passages, said inward ilow and outward flow vanes being fixed to their respective shroud rings and wall structures, means for connecting said impellers v in a unitary structure, said cylindrical spacers, said shroud rings and said inward flow and outward now vanes being located at such radial distances from the axis of the rotor as to render the rotor deflection resistant without the aid of an axial shaft, and stub shafts at the ends of the rotor vfor rotatably supporting the rotor in said casing, said casing comprising annular members welded into a unitary structure, said firstmentioned passages comprisingtwin volutes and said annular members being internally contoured to deiine said twin volutes when arranged end to end.

10. 'I he invention claimed in claim 8 wherein said members are contoured to provide coolin chambers 11."I'he invention claimed in claim 8 wherein shell means are welded to said annular members, with said shell means and said annular members so contoured as to provide cooling chambers.

12. In a centrifugal machine, a casing havingstage fluid passages, a rotor in said chamber, said rotor comprising stage impeller-s arranged end to end, said irnpellers comprising wall structures and cylindrical spacers between the wall structures at the axis of the rotor, shroud rings Dositioned between said wall structures and co-acting with the latter and saidspacers to provide iluid passages generally U-shaped in cross-section, inward flow and outward ilow vanes in the respective second mentioned fluid passages. said inward iiow and outward ilow vanes being fixed to their respective shroud rings and wall structures, means for connecting said impellers in a unitary structure, said means, said shroud rings and said inward ilow and outward ilow vanes being located at such radial distances from the axis of the rotor as to make the rotor deilection resistant without the aid of an axial `shafigstub shafts at the ends of therotor for rotatably supporting the rotor in least one thereof, said peripheral rings having wearing surfaces arranged in co-active relationship with said rst-mentioned wearing surfaces,

13. In a centrifugal machine, a rotor compris- 75 l2 ing a plurality of stage impellers each consisting of an yinlet-side disc and an outlet-side disc, a connector connecting said discs at their axes, and iiuid deflecting vanes connected .to and connecta ing said discs outwardly of their axes to form a rigid shaft-free rotor.

14. In a centrifugal machine, a rotor comprising a plurality of stageimpellers each consisting of an inlet-side disc and an Ioutlet-side disc, a

l connector connecting said discs yat their axes.

and fluid deilecting vanesconnected to and connecting said discs outwardly of their axes, the outlet-side discA of one impeller being attached to the inlet-side disc of the ixnpellelnext thereto thereby forming rigid shaft-free rotor.

15. In a centrifugal machine, a rotor compris- `ing a plurality of stage impellers each consisting of an inlet-side disc and an outlet-side disc, a connector connecting said discs at their axes, and

fluid deiiecting vanes connected to and connect- ,ing said discs outwardly of .their axes, the outletside disc of one impeller being attached tol the .inlet side disc of the impeller next thereto thereby forming rigid shaft-free rotor, and supporting stub shafts connected to and extending outwardly from the ends of the rotor. g

16. In a centrifugal machine, a rotor comprising a plurality of stage impellers each consisting of an inlet-side disc and an outlet-side disc, a

connector connecting said discs at their axes, and

iluid deiiectingvanes connected to and connecting said discs outwardly of their axes to form a rigid shaft-free rotor, the connector of each stage progressively from the iirst. stage being. shorter than the connector of the stage which discharges thereinto whereby the volumetric capacity of the stages progressively decreases from the initial inlet to the final discharge outlet of the rotor.

1'7. In a 'centrifugal machine, the combination 0 of a casing having stage iiuid passages, a.v rotor ln said chamber, said rotor comprising stage impellers arranged end to end, said impellers comprising wall structures and cylindrical spacers between the wall structures at the axis of the rotor, shroud rings positioned between'said wall structures and co-acting with the latter to provide fluid passages generally U-shaped in crc-ss section, inward ow and outward flow vanes in A the respective second-mentioned uid passages, said inward ow and outward ow vanes being xedto, their respective shroud rings and wall structures, meansi'or connecting said impellers into a, unitary structure, said means, said shroud rings and said inward flow and outward flow vanes being located at such radial distances from the axis of the rotor as to make the rotor deflection resistant, said casing having wearing sur- `faces, said shroud rings comprising rst and second sections fixedly connected together, said first sections being respectively connected with said inwardiiow vanes and the second sections being respectively connected with the outward iiow varies, peripheral rings encircling the respective iirst and second sections and anchored to at least one thereof, said peripheral rings having wearing faces arranged in co-active relationship with said first-mentioned wearing surfaces, and inlgt guide vanes for positive prerotation of the uld at the inlets of the respective second-mentioned iiuld passages. tice iirst and second sections and anchored to at 18. In a. centrifugal machine for compressing gas orrvapor, the combination of a casing having stage iluid passages, a rotor in said chamber, said rotor comprising stage impellers arranged end to end, said impellers comprising annular- 13 wall structures arranged in co-axial relationship, shroud rings positionedv between said wail structures and co-acting with the latter to provide fluid passages arranged in series relationship with respectively connected with said outward flow vanes, peripheral rings encircling the respective first and second sections and anchored to atleast one thereof, said peripheral rings having wearing surfaces arranged in co-active relationship with said first-mentioned wearing faces, said wall structures comprising discs welded together, peripheral rings encircling the respective wall structures and anchored to at least one disc thereof, said second-mentioned peripheral rings having wearing surfaces, and wearing surfaces in said casing arranged in co-active relationship with the wearing surfaces on said second-mentioned peripheral rings.

19. In a centrifugal machine of the multistage type, the combination of a casing having a rotor chamber and provided with axially spaced stage fluid passages, said fluid passages having first inlets and first outlets communicating with said chamber, said casing having a suction inlet and 'a discharge, a rotor in said chamber and having axially spaced stage fluid passages provided with second inletsv and second outlets arranged in series communication with said first outlets and first inlets, respectively, to provide a continuous fluid passage extending from said suction inlet to said discharge, said rotor being of such contour with respect to the contour of said chamber as to be axially removable therefrom intact, fluid impinging vanes in said secondmentioned stage fluid passages, said rotor including shroud rings fixedly related thereto and defining one wall of each of said second-mentioned stage fluid passages, said shroud rings each comprising two sections, and means for connecting the sections in each pair one with the other.

20. In a centrifugal machine of the multistage type, the combination of a casing having a rotorv chamber and provided with axially spaced stage fluid passages, said fluid passages having first inlets and first outlets communicating with said chamber, said casing having a suction inlet and a discharge, a rotor in said chamber' and having axially spaced stage fluid passages provided with seco'nd inlets and second outlets arranged in inlets and ilrst outlets communicating with-said chamber, ,said casing having a suction inlet and a discharge, a rotor in said chamber and having axially spaced stage uid passages provided with second inlets and second outlets arranged in series communication with said first outlets and first inlets. respectively. to provide a continuous iiuid passage extending from said suction inlet to said discharge, said rotor being of such contour with respect to the contour of said chamber as to be axially removable therefrom intact, fluid impinging vanes in said seccond-mentioned stage fluid passages, said rotor including axially spaced annular walls, each of said' walls comprising two sections, the sections in each pair being welded one to the other in face to face relationship, annular means attached to and encircling each wall, and inlet guide vanes for zero rotation of the fluid at said second inlets, said inlet guide vanes being attached to said casing.

22. In a centrifugal machine of the multistage type, the combination of a casing having a rotor chamber and provided with axially spaced stage fluid passages, said fluid passages having rst inlets and first outlets communicating with said chamber, said casing having a suction inlet and a discharge, a rotor in said chamber and having axially spaced stage fluid passages provided withsecond inlets and second outlets' arranged in series communication with said first outlets and rst inlets, respectively, to `provide a continuous fluid passage extending from said suction inlet to said discharge, said rotor being of such contour with respect to the contour of said chamber as to be axially removable therefrom intact, fluid impinging vanes in said second-mentioned stage uid passages, said rotor including shroud rings xedly related thereto and deilningone wall of each of said second-mentioned stage fluid passages, said shroud rings each comprising two sections, means for connecting the sections in each pair one with the other, and inlet guidevanes for negative pre- 'rotation of the uid at said second inlets, said v type, the combination of a casing having a rotor` series communication with said first outlets and first inlets, respectively. to provide a continuous fluid passage extending from said suction inlet to said discharge, said rotor being of such contour with respect to the contour of said chamber as to be axially removable therefrom intact, fluid impinging vanes in said second-mentioned stage fluid passages, said rotor including axially spaced annular walls, each of said' walls comprising two sections, the sections in each pair being welded one to the other'in face to face relationship, and annular means attached to and encircling each wall. l

21. In a centrifugal machine roi' the multistage type, the combination of a casing having a rotor chamber and provided with axially spaced stage fluid passages, said fluid passages having first guide vanes being attached to said casing.

23. In a centrifugal machine of the multistage chamber and provided with axially spaced stage fluid passages, said fluid passages having first' inlets and first outlets communicating with said chamber, said casing having a suction. inlet and a discharge, a rotor in said chamber and having axially spaced stage uid passages provided with second inlets and second outlets arranged in series communicationwith said first outlets and firsty inlets, respectively, to provide a continous fluid passage extending from said suction inlet to said discharge, said rotor being of such contour with respect to the contour of said chamber as to be axially removable therefrom intact, fluid impinging vanes in said second-mentioned stage fluid pasages, said rotor including shroud rings fixedly related thereto and defining one wall of each of said second-mentioned stage fluid passages,A said shroud rings each comprising two sections, means for connecting the sections in `each'pair one with the other, and inlet guide varies for positive Drerotation of the uid at said second inlets. said guide varies being carried by said casing.

24. In a centrifugal machine of the multistage type, the combination of a casing having a rotor chamber and provided with axially spaced stage fluid passagesrsaid-fiuid passages having first inlets and first outlets communicating with said chamber, said casing having a suction inlet and a discharge, a rotor in said chamber and having axially spaced stage fluid passages provided with second inlets and second outlets arranged in series communication with said ilrst .outlets ship, annular means attached to and encircling each wall, and inlet guide vanes for zero prerotation of the fluid at said second inlets, said guide vanes being attached to said casing.

25. In a centrifugal machine of the multistage type, the combination of a casing having a rotor chamber and provided with axially 'spaced stage' fluid passages, said uid passages having first inlets and 'first loutlets communicating with said chamber, said casing having a suction inlet and a discharge, a rotor in said chamber and having axially spaced stage fluid passages provided with second inlets and second outlets arranged in series communication with said first outlets and rst inlets. respectively, to provide a continuous fluid passage extending from said suction inlet to said discharge, said rotor being of such contour with respect to the contour oi.' -said chamber as to be axially removable therefrom intact, iluid impinging vanes in said second-mentioned stage fluid passages, said rotor including axially spaced annular walls, each of said walls comprising two sections, thesections in each pair being welded one'to the other in face to face relationship, annular means attached to and encircling each wall, and inlet guide vanes for negative prerotation of the fluid at said second inlets, said guide vanes being attached to said casing.

26. In a centrifugal machine of the multistage type, the combination of a casing having a rotor chamber and provided with axially spaced stage iluid passages, said iluid passages having ilrst inlets and first outlets communicating with said chamber, said casing having a suction inlet and a discharge, a rotor in said chamber` and having axially spaced stage iluld passages provided with second-.inlets and second outlets arranged in series communication with said first outlets and first inlets, respectively, to provide a continuous fluid passage extending from said suction inlet tosaid discharge, said rotor being of such contour with respect to the contour of said chamber as lto be axiallyremovable therefrom intact, fluid impinging vanes in said second-mentioned stage fluid passages, said rotor including axially spaced annular walls, each of said walls comprising two sections, the sections in each pair being welded one to the other in face to face relationship, an-

,nular means attached to and encircling each wall,

and inlet guide vanes for positive pre-rotation of the fluid at said second inlets, said guide vanes being attached to said casing.

27. In a multistage centrifugal machine, a casing, a rotor in said casing composed ot a plurality of connected stage sections including an inlet end disc and an outlet end disc, connectors connecting said discsl at their axial portions, vanes on each of said discs. shroud ring sections integral with the vanes on each of said discs,- meansv connecting the shroud ring section-on one disc 'to the shroud lring section on the other disc-to f detachably connect the disc one to the other near their periphery, anda closure ring detachably connected to one ofsaid shroud ring sections overlapping the joint between the shroud ring sections and engaging the shroud ring section other than the one to which it is connected.

28. In a multistage centrifugal machine, a casing, a rotor in said casing composed of a plurality of connected stage sections including an inlet end disc and an outlet end disc, connectors connecting said discs at their axial portions, vanes on each of said discs, shroud ring sections integral with the vanes on each of said discs, means connecting the shroud ring section on one disc to the shroud ring section on the other disc to detachably connect the discs oneto the other near their periphery, a closure ring detachably connected to one of said shroud ri'ng sections overlapping the joint between the shroud ring sections and engaging the shroud ring section other than the one to which it is connected; the outlet end discv of one stage section abutting and attached to the inletV disc of the adjacent stage section of the rotor,

and a wear ring detachably connected to one of said discs and overlapping the joint formed by the abutting surfaces of the discs.

29. In a multistage centrifugal machine. a casing, a rotor in said casing composed of a plurality of connected stage sections, each of said stage sections including an inlet end disc and an outlet end disc connectors connecting said discs at their axial portions, means detachably connecting said discs near their peripheries, the outlet end disc of one 4stage section abutting and welded to the inlet end disc of the adjacent stage section.

GEORGE F. WI SLICENUS.

REFERENCES CITED The following referencesv are of record in the file of this patent:

UNITED STATES PATENTS France v Apr. 3, 1939 

